凹圓弧比較淺，可用G71編程，假設毛坯直徑為Φ55，夾住棒材，伸出長度為165mm，先手動平端面，打中心孔，頂尖頂緊，將工件坐標系原點設置在工件右端面旋轉中心，使用FANUC系統，數控程序如下：M03S1000T0101G0X55.0Z1.0G71U1.0R1.0G71P10Q20U0.5W0.1F0.2N10G0X30.0G1Z0F0.1X33.8Z-2.0Z-30.0X38.0X50.0W-25.0W-20.0G2Z-105.0R35.0G1W-15.0X52.0W-40.0N20X55.0G70P10Q20G0X150.0Z10.0M03S600T0202G0X39.0Z-30.0G1X30.0F0.03G0X50.0X150.0Z10.0M03S600T0303G0X36.0Z3.0G92X33.0Z-28.0F2.0X32.6X32.3X32.1X31.9X31.8X31.7G0X150.0Z10.0M30切斷程序略，這樣有利於測量和保證尺寸，切斷程序請自行編輯，或手動切斷。
